Electric switch



June so, 1925. mswz Q. U. FLA-ET ELECTRIC SWITCH Filea Jan. 10, 1925 Ytionary switch contacts or jaws 9 and the- Patented June 30, 1925.

UNITED CLARENCE D. PLAT'I, 0F BRIDGEPORT, CONNECTICUT.

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Application filed January 10, 1925. Serial No. 1,560.

T 0 all whom. it may concern:

Be it known that I, CLARENCE D. PLATT, a citizen of the United States of America, residing at Bridgeport, county of Fairfield, State of Connecticut, have invented a new and useful Electric Switch, of which the following is a specification.

My invention relates particularly to an enclosed safety switch having a quick break mechanism.

The main object is to provide a compact, reliable and practical but inexpensive construction.

The invention is particularly applicable to any ordinary enclosed switch having the usual hinged blades and oscillating operating crank. In the preferred form I provide an operating plate member which has two spaced apart projections for alternately engaging one arm of the crank to move it positively back and forth. This crank arm is resiliently connected to one of the projections by a spring so that when the projection ismoved away from the arm it compresses the spring and stores up power to throw the crank with a snap action as soon as the blades have been released from the stationary contact by the positive action of the other projection.

Figure l is a front view of a switch embodying improvements of my invention, the cover of the casing being open and broken Figure 2 is a sectional view on the plane of the line 22 of Fig. 1, looking in the direction of the arrows and showing a side view only of the switch base proper Figure 3 is a section on the plane of the line 3-3 of Fig. 2 looking in the direction of the arrows but on an enlarged scale.

Figure 4 is a perspective view of the oper-- hinged blades 10. In this caseathe blades are suitably connected to an insulating crossbar 11.

The operating crank 12 may be of any suitable design mounted in any suitable" .form of external handle such as 1 1 is usually provided. In this case, however, the important, features are enclosed within the box itself. The plate 15 is what may b termed the operator. This is pivotally mounted on one wall or the box, for instance, by being connected to the bearing washer 16 and the.

outer washer 17 by means of one or more rlvets 12?. This plate 15 is provided with two projections 19 and 20 which extend inwardly into the path of movement of one arm of the crank 12 so that as the plate is oscillated they engage, alternately, the opposite sides of the arm. A link 21 which embraces the crank arm passes through the opening 22 in the projection 19. A spring 23 which is mounted on this U shaped strap link 21. is held in place by the ring member 25 and the turned over or hook-like ends of the link 21.

In assembling the parts the link 21 is slipped around the arm of the crank 12 and inserted through the opening 22. The spring 23 is then slipped on to the link 21. The ring 25 may then be slipped on to the end of the spring. The spring is then compressed by pushing down upon the ring so that the top of the ring passes beyond the turned over ends of the link and when in this position, the ends of the link which have been sprung together to allow the ring to pass over them, will spring back to their original position so that, as pressure upon the ring is released, the ring will seat itself in the turned-over ends of the link and will be'retained in that position for the normal operation of the switch. In order to remove the spring, ring and strap, the assemblingoperation is reversed.

Obviously the link may be of strap form or may be of spring wire.

When the operator 15 is oscillated clockwise, as viewed in Fig. 2, by the handle or otherwise, the projection 19 on the operator plate compresses the spring 23 and swings the link to position as shown in dotted lines. The flange or projecting lug 20 soon engages the crank arm, however, and forcibly moves it and the switch blade towards the open circuit position, as soon as the frictional resistance of the contact jaws on the switch blades decreases to a suflicient extent, the spring 23 acting from the link 21 throws the crank and switch blades suddenly to the open circuit position with a quick break or snap action. In this opening movement the crank arm brings up against the projection 19 which serves as an abutment for it.

A stop 26 may be provided on the outside of the box to limit the throw of the handle and to serve as an anchorage for a sealing wire or look. Another stop 27 may be provided on the inside of the box to limit the throw of thelcrank. By placing this stop 27 in the path of the end of the link 21 it serves to resiliently check the opening movement of the switch.

I claim:

1. A safety switch comprising a casing, a knife blade switch mounted therein, an oscillating crank connected to the switch blades, an oscillating plate operator having spaced-apart projections for engaging opposite sides of one arm of said crank, a spring, and means for connecting said crank arm to said plate to compress said spring when the plate. is being operated to open the, switch. I 7

2. In an enclosed switch an operating crank arm an operator plate having spacedapart pro ections for engaging said crank arm, a link connected to said crank arm, and a compression spring mounted on said link naaaeaa means for operating said plate.

4. In an enclosed switch a switch operating crank arm, an operating plate having a projection, a link connected to said crank arm, a compression spring supported by said link between said projection and the outer end of said link.

5. In a switch a crank arm, an operating plate having a projection for engaging said arm, a strap link embracing said arm and having a hook on the opposite end and a spring on said link interposed between said projection and said hook.

6. In a switch, a crank arm, an operatin plate having a projection for engaging sai arm, a strap link embracing said arm a ring on the other end of said arm and a 5 ring interposed between said projection an said ring.

7. In a switch, a crank arm, an operator having two spaced apart projections adapted to engage said arm, a stra linkembracing said arm, a spring on said link abutting against one of said projectionsand means' for, holding said sprin on said link. .CLKRENCE D. PLATT. 

